BROADENING THE FOOD BASE WITH INDIGENOUS PLANTS
Indigenous food plants are plants that have evolved naturally in a given area. There are also plants that have been introduced and then adapted so well that they have come to be considered local and are referred to as indigenous. The term traditional is also often used for these plants, indicating that they have been used in a given area for a considerable time.
What is important is not so much the terminology but the fact that many of these plants have become an integral part of the local food system and diet. It is not possible to list all the traditional food plants for Africa, as most communities have evolved their own food preferences and habits. There are two broad categories of food plants: those consumed as traditional dietary staples including cassava, yam, plantain, sweet potato, millet and sorghum, and those that serve as ingredients in accompanying relishes and sauces, including a variety of legumes, oilseeds, fruits and vegetables.
Most of the African leafy vegetables, such as amaranth, cowpea, pumpkin and sweet potato, are considered local and traditional food plants. Some of these plants were traditionally gathered from the wild. When this became inconvenient, farming communities began cultivating them. Others remain semi-cultivated, in the sense that farmers do not make a conscious effort to cultivate them, but if these crop varieties appear at the onset of the rains, they are left to grow between planted crops and are consumed when mature.
Traditional food plants have numerous advantages, especially in terms of household food security. In addition to broadening the food base, they increase the food supply and add variety to the diet. They are also beneficial for ecological reasons, as they increase crop productivity, conserve the soil and increase soil fertility. Many traditional crops, such as pumpkin, sweet potato and beans, are interplanted with maize or other cereal crops to act as ecological barriers to disease. When used as a ground cover, traditional vegetables also help prevent soil erosion, reduce evaporation and suppress weed growth. Grown as green manure and ploughed into the soil, they increase the soil's organic matter and improve its structure. Legumes also fix atmospheric nitrogen, enriching the soil for the following crop or for nearby plants.
Cultivated traditional food plants are well adapted to the areas where they are cultivated, and their contribution to the nutrient intake of local communities is significant. Depending on the type, these food crops are important sources of protein, vitamins A and C, calcium and many other micronutrients. In Africa, traditional food plants, including green leafy vegetables, supply an estimated 80 percent of vitamin A and more than two-thirds of the vitamin C consumed. Nuts and oilseeds are also good sources of protein and energy, valuable supplements in children's diets and useful in preparing snack foods. See also Information Sheets 3, "Recipes for nutritious dishes", 4, "Nutritious and tasty snacks for young children", and 5, "Home processing and preparation of weaning foods"; and Home Garden Technology Leaflets 2, "Growing plants for daily nutrition", 3, "Ensuring good family nutrition on a daily basis", 4, "Planting crops for a continuous food supply", and 18, "Processing, preservation and storage".
When the variety in the food base of food-insecure communities narrows, there are serious nutritional consequences because the consumption of certain minerals, vitamins and trace elements is adversely affected. Unfortunately, the production and utilization of traditional food plants is declining, and dietary diversity in rural and urban communities is getting narrower with time. There are many reasons for this. Many introduced vegetables and other food crops are high yielding and have become popular because of their production and processing convenience or the prestige attached to their use. The introduced crops are also often high on the agenda of breeding programmes and commercial seed producers, and their market value is often high. Local species have not received such attention, although their adaptability, nutritional value and place in the traditional diet justify such attention. Although users and promoters of indigenous food plants are well aware of these facts, much more must be done by plant breeders and commercial seed producers to rectify the situation.
The home garden is the ideal place to grow underexploited or endangered plant species. Small areas of the garden can be set aside for growing some of them, and their productivity can be improved by selecting the characteristics most desired, including selecting the species that are inexpensive, drought tolerant and easy to store. By cultivating indigenous crop varieties, the home garden manager not only is an important conservationist but also plays a key role in the improvement of these varieties.
For the nutrient content of foods commonly produced and consumed in Africa, see the food composition table in Appendix 2.
